Most of the elevators installed for handicapped accessibility in private residences have swing doors and a collapsible gate on the elevator cab. Some handicapped accessibility elevators have a power operated swing door at each floor, that is a standard passage door that is swung outward to permit access to the elevator. The problem with automatic swing doors is that a handicapped individual who is entering the elevator in a wheel chair has to position himself far enough away from the door to permit it to swing to its fully open position.
Another problem with the power activated swing door is that once it is open, the passenger still has to manually open the horizontally sliding collapsible gate of the elevator cab to gain entrance. The present invention will permit the automatic opening of the car and the hall doors the full width of the elevator cab by activation of a door open button that is adjacent to each landing entrance.
The commercial passenger elevator has horizontal sliding doors in the car and the hall. The commercial door operators, as in U.S. Pat. No. 3,406,484, require a DC motor that through a series of pulleys and arm linkage are attached to the elevator cab doors to open and close horizontally. This device is not practical on private residence installations, because a sophisticated electrical control is required to operate the direct current motor and the complicated mechanical drive mechanism is too large to be installed on a 3 foot (91.44 cm) by 4 foot (121.92 cm) handicapped residential elevator. The present invention utilizes normal private residence 120 V AC single phase power to operate the doors horizontally.
U.S. Pat. No. 3,431,678 discloses a linear drive actuator that is designed to apply a variable pressure by use of a spring carriage mounted to the actuator block. The spring carriage passes over a system of cams that are used to vary the pressure of the linear drive rollers as they rotate on the shaft. This reference fails to disclose the mechanism of the present invention, which sets the linear actuator for constant pressure along the full travel of the shaft with pitched bearings and adjusts the pressure springs on the linear actuator to provide a kinetic energy of the moving doors of under 2.5 ft-lbs (3.39 newton-meters). This kinetic energy setting is a requirement of Rule 112.4 and 112.5 of the American National Standards Safety Codes for Elevators and Escalators, ANSI A17.1, 1990 edition.
Neither of the above references discloses the conveniently activated and accessible elevator door mechanism of the present invention.